Magnetic fields Definition and 674 Threads

I have attached the drawing. Why is the magnetic field at the location negative and not positive? When I do the right hand rule I point my thumb in the direction of the current and wrap my fingers around the wire. My fingers pointed up for each wire which should be positive z not negative, but...

this is just a naive question from a person who is not a physican, imagine that charged particles ( ions ) could only move in a plane. if a homogeneous magnetic field perpendicular is imposed what would happen ? i think that the particles must come to rest since they emitt electromagnetic...

Hi, I am self taught, and am very interested in learning more about magnetic fields. I have found this site with some great examples of magnetic fields (http://www.coolmagnetman.com/gallery/imageset.html). One of the examples (picture attached), shows a group of five magnets. One is placed...

Homework Statement At a certain point on the Earth's Surface the horizontal component of the Earth's magnetic field is 1.8 * 10^-5 T. A straight piece of wire 2m long and 1.5g lies on a horizontal wooden bench in an east-west direction. When a very large current flows momenterily in the wire...

I can't figure out what is the motion of a charged particle at rest at origin in a constant uniform magnetic field when it is subjected to an oscillating electric field starting t = 0. I need to find the equations representing its motion.

Homework Statement Suppose your physics lab class lasts for a very long time - long enough for you to wind a semi-infinite solenoid. (That spool of copper wire is the gift that keeps on giving.) What is the on-axis magnetic field at the end of the solenoid closest to you (ie., not at...

Hello, I'm in 9th grade looking for some interesting topics to do my science experiment on this year. I'm particularly interested in how magnetic fields affect photons. I know photons are electrically neutral but I'm looking for some "what if?" types of questions. I think somehow being able to...

In electrodynamics, the gauge potentials are not directly measureable, but components of the field strength tensors, which are the electric and magnetic fields are. But why are the electric and magnetic fields, the components of the curl of something not-measureable (the gauge fields)...

Hi! I am a chemist (MSc) working in the field of analytical chemistry. I am using mass spectrometers for years now and I almost have no knowledge about the physical basics. I have read a book about different ion optics, but it was still not deep enough. Could you give me some advice where...

Hello everyone, I hope this is in the right section. if not i'll be happy to move it. Anyways i have a few questions about general concepts so this may be a lengthy one. Any and all help is REALLY appreciated. I have attached two photos of something explaining the creation of a magnetic...

Using Magnetic Fields in Place of Heat Shielding Joshua “FireStorm” King Note: All Graphs are in SI base units Note 2: I strongly recommend downloading the document version of this post as the equations are actually readable there. RTF Format: Docx Format: Introduction: The Problem I'm a real...

¿ Can diff. EM frequencies create diff. magnetic fields with diff. properties ? I understand that a magnetic field is generated via moving charged particles . Electricity and magnetism are linked through electromagnetism . Electromagnetism can be in different wavelengths and frequencies but...

Homework Statement A) Find the magnitude of the net magnetic field at point P and point Q B) Reverse the directon of the current for the wire on the x-axis Homework Equations B = μ0I/2πr The Attempt at a Solution Solution attempt attached. Only attempted part A, since I probably won't get...

Where did the formula r=mv/Bq come from in my answerbook for my grade 12 physics? Thanks.

Hello, I am curious as to how this works exactly. What I have a question regarding is having multiple solenoids within 2 inches of each other. Say we have a square, and on each corner is a solenoid standing up, so the corner is center on the axis going through the solenoid. All of them have...

Hello again PF, I've been doing some light reading on different magnetic fields of different gas giants, and what was really fascinating is how different Uranus and Neptune's fields were from Jupiter's and Saturn's, due to their different mass and composition? What I read was that both of...

So let's say a water molecule is stuck between a positive magnetic field and a negative magnetic field ?

I don't feel like this is a homework question, more like a curiosity question. If I'm wrong then feel free to move it to the homework section and my apologies. I know how the RHR works for magnetic forces and I can apply it with no problem, however I'm not a physics major so maybe I'm missing...

Homework Statement http://i.imgur.com/mgIkS.png Two long parallel wires carry currents of 2.03 A and 8.83 A. The magnitude of the force per unit length acting on each wire is 4.49*10^5 N/m. Find the separation distance of the wires expressed in millimeters. Homework Equations I'm not...

what is magnetic field and ? how it forms ?

I have read that the electric and magnetic fields are always "perpendicular". Is that true? And if so, does that mean the inner product of the two vectors is zero? E_x * B_x + E_y * B_y + E_z * B_z = 0 ? Also, is there any special meaning in electrodynamics to the quantity: | B |^2...

Since a changing current creates a magnetic field, and if there's a wire near by, the magnetic field will induce a current in that wire. What is needed / what does it take to turn that magnetic field into EM radiation such as a radio wave? Or is it purely just the frequency of the current, so...

Homework Statement A beam of photons, originally at rest, is accelerated horizontally between the plates of a parallel-plate capacitor, the potential difference of which is 1000 V and has a separation of 1.0 cm. The particle enters a region wher a uniform magnetic field, B=0.913T (directed out...

Restrictors and capacitors can be put in series or in parallel to amplify their affects. Hydraulic pistons and pumps can be put in series to intensify pressure. Springs can be put in parallel or in series to come up with alternate, combined properties. However, I can't think of a case...

The equation for the force of a magnetic field on a moving charged particle would say no: F = q * v x B, which means the force is always perpendicular to v, and never has a component along v. Thus a magnetic field can't accelerate a particle, only deflect. This is correct, right? If...

I just have a question based on a toroidal conductor. I know that the magnetic field would run in a circle (http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/imgmag/tor.gif). I am wondering if that magnetic field would do anything. For example, if I dropped something charged into there, would...

Hello everyone Ive got myself into a muddle over the forces involved in magnetic fields. I understand that if a current carrying wire is perpendicular to a magnetic field then it will experience a force according to Flemings Left Hand Rule. Now if a wire is to move in the same direction...

Greetings, I see graphs of the amplitude of a photon's fields over time, but no illustrations of the shape of the field at any instant in time. Are the fields confined to planes like they look in the graphs? Or do they extend in three dimensions like the field around a magnet? Thanks

Homework Statement when the switch is closed , describe what will happen to the meter reading, the direction of the current flow, if any, and the magnetic fields produced in the two coils Homework Equations none The Attempt at a Solution the current flow is shown in the pic...

Hi guys, So far I am aware of these rules regarding magnetic fields/direction of current: A compass needle point is attracted to a south pole (or inversely repelled by a north pole). Left hand rule #2: For an electromagnet, point thumb toward north pole, fingers curl in direction of current...

A plasma is when electrons become unbound by their atoms. So does that mean that you can get a different plasma for all different types of atoms (like gold plasma and helium plasma)? Also the electrons are not free as they are bound to the plasma (but not individual neuclei) by the magentic...

Homework Statement see attached. this question is from a test that doesn't allow any calculators and usually makes students solve the problem in 1 minute max. Homework Equations perhaps biot savart is to be used? but I doubt that can be done in the time limit... The Attempt at a...

Homework Statement A 2.50 meter long copper rod has a mass of 0.25 kilograms. A magnetic field of 0.15 Teslas is oriented horizontally from south to north. a.) What is the minimum current in the rod that would allow it to "levitate" in this magnetic field? b.) What is the direction of the...

Homework Statement Why are magnetic forces not always conservative? I came across this question and to my knowledge they are always conservative...can anyone explain why they wouldn't be?

I'm going in circles on units (or perhaps more accurately different unit systems). The two my professor has chosen to work in are Gaussian units and MKSA units. My problem is one of lack of understanding; are the units of measure for electric and magnetic fields in these systems: Gaussian: E...

my query is : The electric and magnetic fields don’t squeeze or stretch then how is Doppler Effect of light possible? In the phenomenon of Doppler Effect, light emitted from a moving source is detected to have different frequency. If this is taken on terms of detecting the no. of waves...

An electron is moving by a wire that is carrying 10 amps of current e-----------------------------> (electrons) 0===============I-->======== (wire) if the electron is moving by the wire at 2.5x10^6 m/s and is .33 m from the wire how do I find these two answers? A) The magnetic field...

An electron is moving through a 0.002T magnetic field as described below. Show the direction the electron will be pushed by the magnetic field, and calculate teh amount of force exerted on the electron if the electron is moving at 3x10^5 m/s here is what the paper looks like x x x x...

Do magnetic field is produced in all the following 3 cases? Case 1: An isolated electron moving linearly with constant velocity in space. Case 2: An electron moving inside a copper conductor linearly(current). case 3: A ball( made up of many molecules, in-turn atoms, in-turn electrons...

let's say we have a square piece of metal and we put this piece in a variable magnetic field, would it get heated? is this the idea of a current? If we have a rotating metal disk (as the case of a saw for instance), and then we put this rotating disk in a constant uniform magnetic field such...

How can a coil of wire help bring the net flux in a changing magnetic field back to zero?

let's say we have a square piece of metal and we put this piece in a variable magnetic field, would it get heated? is this the idea of a current? If we have a rotating metal disk (as the case of a saw for instance), and the we put this rotating disk in a constant uniform magnetic field such...

Homework Statement I am a HS student researching the penetration depths of magnetic fields in conductors. Specifially, I am investigating the exponential decay of eddy currents induced within a conductor in the presence of a rapidly changing magnetic field. I am a bit confused as to why the...

1. Homework Statement A) A current loop is placed in a uniform magnetic field that is directed out of the page as shown. The current is clockwise as shown. What, if anything, happens to the loop? B) Consider the following rigid coil that is placed in a uniform magnetic field that is...

Good night, I'm trying to do a model of the maglev at small scale, but I'm having a lot of problems to levitate and have stability. I have already read Earnshaw theory, but in youtube i see many models working, but when i try do replicate doesn't work. Now i have a rail way with...

Homework Statement The two main concepts in this chapter are: Moving charges create magnetic fields & Magnetic fields exert forces on moving charges. You have decided to make a home made cyclotron (particle accelerator). You decide to use a household circuit use a 120V, 15 Amp circuit. If...

Homework Statement 4. A long straight wire lies along the z-axis and carries an 8 A current in the +z direction. Find the magnetic field (magnitude and direction) produced at x=0.4 m, y=0, z=0.3 m by a 0.7 mm segment of wire centered at the origin. Homework Equations dB=(mu/4pi)(I[dL x...

How do I find the direction of these things? The right hand rule only works when I have the current and it's asking for clockwise/counter-clockwise, and the left hand rule only works when I have two of the three: Current, Magnetic Field, and Force. Example...

Homework Statement Consider three straight infinitely long (parallel to each other), equally spaced wires (with distance d), each carrying a current I in the same direction. (a) Calculate the locations where magnetic field is zero. (b) Sketch the magnetic field line pattern. (c) If the...

recently i came to know that the jets of gases from black holes are due to magnetic fields...so in effect does this field overpower the effect of the gravitational pull of the BH?